Since 2004 Geim et al. prepared graphene by repeatedly stripping the graphene off natural graphite using an adhesive tape, graphene has caused an unprecedented sensation in the scientific community due to its unique monolayer lamellar hexagonal honeycomb lattice structure, and its unique excellent performance and great potential application value have attracted extensive attention around the world. In the chemical bonding mode, carbon atoms constituting the two-dimensional structure of the graphene are hybridized in a sp2 mode, which makes the carbon atoms form a stable C—C bond with three adjacent carbon atoms through an a bond, thereby enabling the graphene to have very high mechanical properties. At the same time, π electrons provided by a large number of carbon atoms perpendicular to the plane of the graphene form a large π bond, and electrons can move freely therein, so the graphene usually has excellent conductivity. For example, the graphene is a zero-bandgap semiconductor, the moving speeds of the electrons therein can be up to 1/300 of the velocity of light, and the migration rate of graphene carriers is up to 2×105 cm2·V−1·S−1 and so on. In addition, the graphene also has good thermal and magnetic properties. Due to its higher specific surface area, the graphene has huge potential applications in the fields of supercapacitors, hydrogen storage, monomolecular chemical sensors, etc.
At present, the graphite oxide reduction method is the main method for preparing the graphene. The method includes: performing strong oxidation treatment on graphite to obtain graphene oxide, then stripping off the graphene oxide to prepare the graphene oxide, and finally performing a reduction treatment to obtain the graphene. Since the structure of the a graphene sheet layer can be seriously damaged during the strong oxidation process, although the electronic conjugate structure of the graphene sheet layer is partially restored after the reduction treatment, various performance indexes of the prepared graphene material still have greater difference as compared with high-quality graphene. In addition, the oxidation process of the graphite usually requires a large amount of strong acid oxidants, such as concentrated sulfuric acid, concentrated nitric acid, potassium permanganate and the like, and hydrazine hydrate or sodium borohydride and other toxic chemicals are also needed in the reduction process, thereby not only resulting in high energy consumption, low efficiency and high cost, but also leading to serious pollution, as in invention patents CN102897756, CN102897757 and so on. If the graphene is prepared by an epitaxial growth method, a carbon source gas (methane, ethane, acetylene or the like) needs to be injected at a high temperature, the gas decomposes and forms the graphene on a substrate, this method requires a high temperature that is higher than 1000° C., and hydrogen is needed to serve as a reducing gas, the requirements on production conditions are strict, the reaction time is long, the yield is low, and the use of a large number of dangerous gases increases the production cost and also limits the further application of the graphene. Moreover, it is very difficult to strip off the graphene from the substrate (such as copper, nickel, silicon carbide and other substrates), strong acid corrosion, high temperature gasification and other extreme methods are usually adopted, thereby not only leading to high cost and environmental pollution, but also damaging a finished product of the graphene, as in invention patents CN102903616, CN102891074 and so on.
Because of this special structure, the graphene has excellent physical and chemical properties, and how to use it in macrostructures or functional materials becomes the focus of attention in the scientific community at present. However, due to the poor dispersion of the graphene in a matrix, it is difficult to achieve uniformity; and moreover, since it is generally difficult for the graphene to form strong interface combination with the matrix, it becomes a difficulty in the development of graphene composite materials.
The graphene with orientated growth and uniform distribution can be designed and prepared into oriented graphene arrays in various shapes according to requirement. In applications, the problem of difficult dispersion can be avoided effectively, and the excellent performance of the graphene along the plane can be fully utilized, therefore the graphene has a broad application prospect.
Therefore, there is an urgent need to develop a method, which uses novel raw materials, is simple and feasible in method, has no special requirement on equipment, and is low in cost, high in efficiency, free of pollution, free of emission, and easy to popularize and use, and by means of which the problems of high cost, low efficiency, poor quality, poor dispersion, poor compatibility and the like in the existing graphene preparation technology can be solved, and a highly planar oriented graphene material can be obtained.